Yankstain

An annoying American who feels the need to constantly assert their country's superiority, unaware that doing so actually demonstrates insecurity and self-doubt.

See the definitions for America
And also wankstain

The internet has been full of Yankstains since "9/11," and if I have to read another badly-spelled piece of crap about how shit the French are, I swear I will take an aeroplane and crash it where the sun doesn't shine.

by Voice of reason (the plane part was a joke, though April 24, 2003